Vania



(NoModel.)

W. A. GONNE-R &.J. W. MARSH. ELECTRIC CABLE.

No. 466.2468. Patented Dec. 29, 1891.

Att

ma noms versus co., now-umu., wnmmcm. u. c.

UNITED STATES:

PATENT OFFICE.A

WILLIAM A. CONNER AND JOSEPH W. MARS-H, OF PITTSBURG, PENNSYL- VANIA,ASSIGNORS TO THE STANDARD UNDERGROUND CABLE COM- PANY, OF SAME PLACE.

ELEC-rule CABLE.

SPECIFICATION forming' part 0f Letters Patent NO. 466,268, dated.December 29, 1891.

Application filed February 10, 1890. Serial No. 339.809. (No model.)

invented or discovered a certain new and useseparated by a certainthickness of insulationy ble at dierent stages of manufacture.

ful Improvement in Electric Cables, ofiwhich improvement the followingis a specification.

The invention described herein relates to certain improvements inelectric cables. It is necessary in ,the manufacture of electric cablesthat the Wiresv or conductors should be in order to prevent leakage fromone to another adjacent thereto. This end has heretofore been attainedby first fully insulating each conductor-that is to say, surroundingeach with insulation having a thickness equal to half the thickness ofinsulation required between adjacent Wires. The Wires thus insulatedwere then laid up into a cable by a suitable twisting or strandingmachine. This separate insulation of each conductor and the subsequenttwisting of the conductors to form the cable greatly increases theexpense and labor of manufacture, and the cable so made is less pliablethan desired.

The object of this invention is to so arrange the Wires thereof as tomaintain proper insulation and yet render the cable more iiexible andreduce the Vcost of manufacture; and it is a further object of saidinvention to so ar.

range the wires that when employed in pairs as a metallic circuit themembers of such pairs shall be separated a sufficient distance toovercome any retardation of current, and this without any undue increasein the size of the cable.

In the accompanying drawings, forming a part of this specification,Figure 1 is a View in elevation of a cable embodying our invention,partsbeing removed to illustrate the ca- Fig. 2 is a transversesectional'view of the cable, and Fig. 3 is a similar view of a modifiedform of the cable.

The central core l may be formed of a wire or conductor fully insulated,as shown in Fig. 2, or may be formed of a strand of ber ofnon-conducting material. Around this Central core are placed a series ofwires 2, either entirely bare or only thinly or indifferently coveredwith insulating material. A strand or strip 3 of fibrous or othernon-conducting material is interposed between adjacent wires, saidstrand or strip having a diameter equal to the thickness of insulatingmaterial required between wires in the same layer. The Wires 2 andalternating non-conducting material is preferablyr arranged spirallyaround the core l in a manner similar to laying up the strands of a wirerope. The wires and non-conducting material are bound in place by alayer 4 of non-conducting material, preferably formed by Wrapping orbraiding a fibrous material around them. This layer 4 should also bemade of a thickness equal to the thickness of insulation requiredbetween adjacent conductors, so that the wires 2 of the first layer maybe separated the desired distance from the wires of the next layer. Uponthe Wrapping or layer 4 of insulating material is arranged in properalternation another series of wires 5 and strands 6 of nonconductingmaterial, as described, for the formation of the first series. Thissecond series of alternating Wires and non-conducting strands are boundin place by a wrapping or braiding 7 of iibrous material of a thicknessapproximately equal to that of the layer et. Upon this second layer ofnon-conducting Inaterial may be placed a third series of alternatingVWires and insulating-strands, which are similarly covered with a thirdlayer of non-conducting material, and these operations continued untilthe desired nury q f conductors have been incorporated in'tne cable. Thelast layer of non-conducting material may orl may not be covered with asheathing S, of lead or other suitable material, in accordance with theuse to which the cable is to be used.

Vhen metallic circuits are employed, it is customary to employ adjacentconductors for such circuits, so as to avoid confusion in makingconnections, and it is desirable that the wires forming the circuitshould be separated a greater distance from each other than adjacentwires of adjoining circuits. Hence in the manufacture 0f this class ofcable the strand of non-conducting material interposed between theconductors forming the circuit is made somewhat Wider than the strandsinterposed between adjacent Wires of independent circuits, as shown inFig. 3. In this form of cable the layer 4T, separating the severallayers or series of Wires, is made of a thickness equal to the thicknessof strands separating adjacent circuits.

It will be readily understood that a cable constructed as described willrequire less labor and time in its construction and the insulation ofthe conductors and the laying up or arrangement thereof into the form ofa cable be effected simultaneously.

W`e claim herein as our invention- An electric cable havingl a series ofconductors adapted to be used in pairs for metallic circuits, the twoWires of a pair 0r circuit being separated from each other a greaterdistance than the adjacent Wires of adjoining circuits, substantially asset forth.

In testimony whereof we have hereunto set

